Recent findings indicating a Cl ion transport defect in human airway submucosal gland cells suggest that these cells represent an important target for gene therapy. The selective accumulation of CF mRNA in these cells further suggests the presence of gland cell-specific regulatory elements in the CFTR gene. The availability of human gland cell cultures should facilitate the identification of these elements, providing information needed for the design of optimal gene delivery vectors. In the proposed studies, human gland cell cultures will be used to: (l) analyze endogenous CFTR gene transcription using Northern blots, primer extension, and S1 nuclease protection assays, (2) survey potential regulatory regions of the CFTR gene by chromatin nuclease hypersensitivity assays, and (3) identify CFTR promoter elements that specify gland cell-specific expression by means of transfections with CFTR promoter-reporter gene constructs. Information obtained from these studies should permit construction of a minimal length CFTR-based promoter able to direct high level selective expression in gland cells.